The Last House on the Left, 1972 version. It wasn't really terrible, though some of the themes, like sexual torture, were worse in it than in the newer one. I was thrown off though by the jumps between the torture and the bumbling cops. They made me angry since they could have saved them if they stopped being such idiots and also no cops, even the boonies kind, act like that.

Overall, not something for anyone below 18 and only if you can handle some sick themes, even if the imagery wasn't gory.